JP2013211346A - Resist adhesion-increasing agent, and method for manufacturing copper wiring line - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a resist adhesion-increasing agent for a copper film surface treatment to be executed to form a copper wiring line faithful to a resist pattern by achieving good adhesion of a resist film to a copper film surface, and reducing an amount of side etching by an etchant at the time of etching when forming the resist film on the copper film surface in the process of forming the copper wiring line from a copper film in manufacturing a display device such as LCD or EL display; and a method for manufacturing such a copper wiring line.SOLUTION: The resist adhesion-increasing agent comprises: 1.5-20 wt.% of an organic acid; 0.0007-0.73 wt.% of chloride ions; and 0.00003-3.7 wt.% of ammonium ions with the balance including water. The molar concentration ratio of the chloride ions to the ammonium ions is in a range of 0.1-10. The method for manufacturing a copper wiring line by use of the resist adhesion-increasing agent comprises the step of forming a photosensitive resist film on a copper film after surface treatment thereof, whereby the adhesion of the photosensitive resist to the copper film surface is enhanced.

Description

  The present invention provides a method for forming a resist film on a copper film surface in a process of forming a copper wiring from a copper film on a substrate surface in manufacturing a display device such as a liquid crystal display (LCD) or an electroluminescence (EL) display. The present invention relates to a resist adhesion improver suitable for copper film surface treatment to improve the adhesion of the film to the copper film surface and a copper wiring manufacturing method.

  In high performance LCDs and EL displays, copper has begun to be used as a wiring material to replace aluminum. The reason why copper is desirable is that it has a lower resistivity than aluminum and enables finer wiring. Therefore, the opening can be designed widely and switching can be driven at high speed. Because of that.

  As a method for producing a copper wiring, generally, after forming a copper film on the substrate surface by vapor deposition or plating, a photosensitive resist film is formed on the copper film, and a pattern mask is formed on the resist film. A method of forming a copper wiring through all exposure, development of a resist film after exposure, etching of a copper film portion from which the resist film has been removed by development, and subsequent resist film peeling is used.

  In this case, when forming a resist film on the surface of the copper film, a very high degree of adhesion between the copper surface and the resist film is required in order to form wiring exactly according to the resist pattern in the subsequent etching process. The Conventionally, technical examinations for forming a resist film on a copper film with good adhesion include examination of a technical problem of resist and examination of a surface treatment method for a copper film.

  Among these, studies on the surface treatment of the copper film include, for example, a removal treatment of the copper film surface and an oxide film, and a copper surface roughening treatment, for which physical polishing of the copper film surface, or Chemical polishing (soft etching) with chemicals is performed. In physical polishing, a cleaning liquid containing an organic acid and an ammonium compound is used for the purpose of removing a brush that has been polished or particles adhering to the polished surface (see, for example, Patent Document 1). The technique disclosed in Patent Document 1 is intended to be applied to a manufacturing method including a step of cleaning a semiconductor substrate and removing contaminants after planarizing copper interconnects by a CMP technique. This contaminant is also a contaminant including particles generated by polishing, and there is no mention of copper film surface treatment before resist coating. In addition, the contaminant is removed to ensure a flat surface by polishing. The problem of improving the adhesion of the resist is not intended at all, and the possibility remains unclear. Moreover, since the substrate size is large in the manufacture of LCDs and EL displays, it is difficult to apply physical polishing, and no technique that can be applied to a large-scale substrate is disclosed.

  On the other hand, in chemical polishing, a cleaning liquid containing ammonium fluoride, ammonium acetate, or the like (for example, see Patent Document 2), a sulfuric acid-based cleaning liquid, a hydrochloric acid-based cleaning liquid (for example, see Patent Document 3), or the like is used. Methods for chemical treatment are known. In the technique disclosed in Patent Document 2, a cleaning liquid is used for the purpose of removing a product after dry etching, and it is not intended to be used in a resist pattern forming process before etching, and its possible Sex remains unknown. Further, in the technique disclosed in Patent Document 3, copper oxide on the copper surface of the lead terminal is used to ensure conductivity in the manufacture of a resin package that adheres to a resin through a copper oxide layer formed by oxidizing the copper surface. A cleaning solution is used for the purpose of removing the layer, and a copper oxide layer is formed rather to increase the adhesive strength with the resin, and the problem of improving the adhesion of the resist by cleaning is not intended at all.

Special table 2002-506295 gazette JP 2004-342632 A JP 2009-260280 A

  As a result of investigation by the present inventors, when a photosensitive resist film is formed on a substrate that has been subjected to a surface treatment of a copper film using such a cleaning liquid, the amount of side etching in etching is almost the same as that in which no surface treatment was performed. It was found that there was no difference, and therefore it did not contribute to improving the adhesion of the resist film to the copper surface.

  The present invention relates to a surface treatment of a copper film on a substrate surface, particularly when a resist film is formed on a copper film surface in a process of forming a copper wiring from a copper film in manufacturing a display device such as an LCD or an EL display. Resist adhesion improver for copper film surface treatment to improve the adhesion to the copper film surface, reduce the amount of side etching during etching with an etchant, and form copper wiring faithful to the resist pattern And it aims at providing a copper wiring manufacturing method.

The present invention contains 1.5-20% by weight of organic acid, 0.0007-0.73% by weight of chloride ions, 0.00003-3.7% by weight of ammonium ions and the balance water, and The resist adhesion improver has a molar concentration ratio of chloride ion to ammonium ion in the range of 0.1-10.
The present invention also includes a step of forming a photosensitive resist film on a copper film formed on the surface of the substrate, and copper exposed to the photosensitive resist film through a pattern mask and developed, from which the resist film has been removed. In the copper wiring manufacturing method including the step of etching the film part with an etching solution, when forming the photosensitive resist film on the copper film, after treating the copper film surface with the resist adhesion improver, It is a copper wiring manufacturing method characterized by forming a photosensitive resist film on a copper film.

  Since the present invention improves the adhesion between the copper film and the resist when applied to the formation of copper wiring by etching in a display device such as an LCD or EL display with the above-described configuration, the side at the time of etching with an etching solution is improved. The amount of etching can be reduced, and copper wiring faithful to the resist pattern can be manufactured.

FIG. 1 is a graph showing changes in the amount of side etching in a resist adhesion improver in which chloride ions are fixed at 0.066 wt% and ammonium ions are 0.034 wt% and the concentration of organic acid (citric acid) is changed. It is.

  The resist adhesion improver of the present invention comprises 1.5 to 20% by weight of organic acid, 0.0007 to 0.73% by weight of chloride ion, 0.00003 to 3.7% by weight of ammonium ion and water. The molar concentration ratio of chloride ions to ammonium ions, that is, the ratio value represented by [chloride ion molar concentration] / [ammonium ion molar concentration] is in the range of 0.1 to 10.

  The organic acid may be a water-soluble organic acid, for example, a monovalent carboxylic acid selected from acetic acid, formic acid, butyric acid, etc., a polyvalent carboxylic acid selected from citric acid, succinic acid, malonic acid, succinic acid, and the like. Among these, carboxylic acid containing an unsaturated bond selected from acrylic acid, methacrylic acid, maleic acid and the like is included. These organic acids may be used alone or in combination. Of these, citric acid is preferred.

  The amount of the organic acid is 1.5 to 20% by weight, preferably 1.5 to 17% by weight, more preferably 3 to 7% by weight, based on the resist adhesion improver. When it is less than 1.5% by weight and exceeds 20% by weight, it does not contribute to the reduction of the side etching amount, and the effect of improving the adhesion between the copper film and the resist cannot be obtained.

  In the chloride ion, examples of the supply source include hydrochloric acid, hydrochloride of an alkali compound, and the like. Examples of the alkali compound hydrochloride include inorganic alkali compound hydrochlorides such as ammonium chloride, sodium chloride and potassium chloride, and organic alkali compound hydrochlorides such as ethylamine hydrochloride and diethylamine hydrochloride. These chloride ion supply sources may be used alone or in combination. Of these, hydrochloric acid and ammonium chloride are preferred in view of the problem of metal contamination and cost.

  The amount of the chloride ion supply source is such that the chloride ion is 0.0007 to 0.73% by weight with respect to the resist adhesion improver, preferably 0.0007 to 0.066 weight. %.

  Examples of the supply source of the ammonium ion include ammonia water, ammonium halides such as ammonium chloride and ammonium bromide. These ammonium ion supply sources may be used alone or in combination. Of these, ammonia water and ammonium chloride are preferable.

  The amount of the ammonium ion supply source is such that the ammonium ion is 0.00003 to 3.7% by weight, preferably 0.00003 to 0.74% by weight, based on the resist adhesion improver. is there.

  As a supply source of the chloride ion and the ammonium ion, ammonium chloride is preferably used.

  When the ammonium ions and chloride ions are less than the above range and exceed the above range, they do not contribute to the reduction of the side etching amount, and the effect of improving the adhesion between the copper film and the resist cannot be obtained.

  In the resist adhesion improver of the present invention, the molar concentration ratio of chloride ion to ammonium ion is in the range of 0.1 to 10, preferably in the range of 0.1 to 5, more preferably 0.5. It is the range of ~ 5. When chloride ions or ammonium ions are contained in a molar concentration ratio of chloride ions to ammonium ions that is outside the range of 0.1 to 10, it does not contribute to reduction of the side etching amount, and adhesion between the copper film and the resist. The effect of improving the properties cannot be obtained.

  In the resist adhesion improver of the present invention, the organic acid is 3 to 7% by weight, the molar concentration ratio of chloride ion to ammonium ion is 0.6 to 4.9, chloride ion and ammonium ion. The total content of is preferably 0.00076 to 1.07% by weight.

In the resist adhesion improver of the present invention, in addition to the essential components described above, other components may be blended within a range that achieves the object of the present invention. Examples of the other components include:
Surfactant etc. can be mentioned.

  In the resist adhesion improver of the present invention, the blending amount of water is the remainder of the blending amount of the above-mentioned organic acid, chloride ion, ammonium ion, and other components, if applicable. is there. The water is preferably one having as little impurities as possible, and pure water is generally used.

Preferred examples of the formulation are as follows, for example.
(1) 1.5 to 20% by weight of organic acid, 0.0007 to 0.73% by weight of chloride ion, 0.00003 to 3.7% by weight of ammonium ion, And a remaining amount of water, wherein the molar concentration ratio of chloride ion to ammonium ion is in the range of 0.1 to 10.
(2) The organic acid is 1.5 wt% or more and 20 wt% or less, the chloride ion is 0.0007 wt% or more and 0.73 wt% or less, the ammonium ion is 0.00003 wt% or more and 0.74 wt% or less, And a remaining amount of water, and a molar ratio of chloride ions to ammonium ions is 0.5 or more and 5 or less.
(3) 1.5 to 17% by weight of organic acid, 0.0007 to 0.73% by weight of chloride ion, 0.00003 to 3.7% by weight of ammonium ion, And a remaining amount of water, wherein the molar concentration ratio of chloride ion to ammonium ion is 0.1 or more and 10 or less.
(4) The organic acid is 3 wt% or more and 7 wt% or less, the total amount of chloride ion and ammonium ion is 0.00076 to 1.07 wt%, and the molar concentration ratio of chloride ion to ammonium ion is Resist adhesion improver that is 0.6 or more and 4.9 or less.
(5) The organic acid is 1.5 wt% or more and 17 wt% or less, the total amount of chloride ions and ammonium ions is 0.00077 to 4.42 wt%, and the molar concentration of chloride ions with respect to ammonium ions A resist adhesion improver having a ratio of 0.1 or more and 5 or less.

  The resist adhesion improver of the present invention can be prepared by mixing the required amounts of the above components by a conventional method, for example, stirring and mixing at room temperature (for example, 25 ° C.).

  The resist adhesion improver of the present invention can be used for applications aimed at improving resist adhesion on a copper surface. Specifically, for example, a step of forming a photosensitive resist film on the copper film formed on the substrate surface, and the resist film formed by exposing and developing the photosensitive resist film through a pattern mask is removed. A copper wiring manufacturing method including a step of etching the copper film portion with an etching solution, in detail, for example, a step of forming a photosensitive resist film on the copper film formed on the substrate surface, In a copper wiring manufacturing method including an exposure process through a pattern mask, a development process of a resist film after exposure, and an etching process with an etchant of a copper film part from which the resist film has been removed by development, onto a copper film Before forming the photosensitive resist film, the copper film surface is washed and then the photosensitive resist film is formed on the copper film so that the resist adheres to the copper film when patterning on the substrate. The improved can be configured faithfully reproduced copper wire production method a resist pattern by reducing the amount of side etching by etching. In this case, the step of forming a photosensitive resist film on the copper film formed on the surface of the substrate, and the copper that is exposed to the photosensitive resist film through a pattern mask and then developed, and the resist film is removed. For the process of etching the film portion with an etching solution, a known process can be employed.

  Further, in the copper wiring forming method, a photosensitive resist film is formed on a surface-treated copper film using the resist adhesion improver of the present invention, and the copper wiring is formed by etching with an etching solution. In order to improve the adhesion of the resist to the copper film surface, the copper film surface treatment performed in advance before applying the photosensitive resist to the copper film surface is performed by treating the copper film surface with a resist adhesion improver. The copper wiring formation method which improved adhesiveness can be comprised. Using the resist adhesion improver of the present invention as a copper film surface treatment method performed in advance for improving the adhesion of the photosensitive resist to the copper film surface is a technique first achieved by the present inventors. .

  In these cases, as the processing conditions for the copper film, the temperature of the resist adhesion improver may be room temperature (for example, 25 ° C.) or may be heated (for example, 30 to 40 ° C.), and the substrate processing time is generally For example, 1 to 10 minutes. For the treatment, methods such as an immersion method, an immersion stirring method, and a shower method can be used. Moreover, you may wash | clean a resist adhesive improvement agent by the rinse process by a pure water as needed after a process is complete | finished.

  The resist adhesion improver of the present invention, the copper wiring manufacturing method of the present invention, and the copper wiring forming method using the same are all suitable for copper wiring formation of large substrates in the production of display devices such as LCDs and EL displays. Can be applied.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, the following description is only for description and the present invention is not limited to these Examples.

  Table 1 shows the composition of each evaluation solution used in Examples 1 to 19 and Table 2 in Comparative Examples 1 to 20, and the results of the following evaluations using these evaluation solutions.

1. Side Etching Amount Measurement A Ti film was formed on a Si substrate, and a substrate on which a copper film (1000 mm) was further formed was allowed to stand at 23 ° C. for 2 months to impart contamination to the copper surface. After immersing the substrate in an evaluation solution at 35 ° C. for 2 minutes, a photosensitive resist film is formed by a conventional method, and after exposure through a mask, the resist is developed, and the copper film portion where the resist is removed is formed. Etching with an etchant was performed. About the obtained etching shape, the amount of side etching by etching was compared by cross-sectional shape observation using the scanning electron microscope. In addition, the side etching amount described the relative numerical value with the following symbols compared with the comparative example 1 (an evaluation liquid is a pure water).
AAA: Side etching amount less than 60% of Comparative Example 1 AA: Side etching amount of 60% or more and less than 80% of Comparative Example 1 A: Side etching amount of 80% or more and less than 100% of Comparative Example 1 B: Comparison Side etching amount C of 100% or more and less than 120% of Example 1: Side etching amount of 120% or more of Comparative Example 1

  From the results of Examples 1 to 19, it was found that the resist adhesion improver of the present invention contributes to the improvement in adhesion between the copper film and the resist because the amount of side etching is reduced as compared with Comparative Example 1. did. On the other hand, in the compositions shown in Comparative Examples 2 to 20, in any case, compared with Comparative Example 1, the amount of side etching was almost the same or larger, so the adhesion between the copper film and the resist was improved. It has been found that there is no effect or that the adhesion between the copper film and the resist is deteriorated.

  FIG. 1 shows changes in the amount of side etching when the chloride ions are fixed at 0.066 wt% and the ammonium ions are fixed at 0.034 wt% and the concentration of the organic acid (citric acid) is changed. From FIG. 1, when the citric acid concentration is 1.5 wt% or more and 20 wt% or less, the chloride ion concentration is 0.066 wt%, and the ammonium ion concentration is 0.034 wt%, the side etching amount is Comparative Example 1 (Evaluation Solution). It was found that the resist adhesiveness was improved because of the relative reduction compared to pure water.

  Since the resist adhesion improver of the present invention can reduce the amount of side etching in etching by improving the adhesion between the copper film and the resist, in the manufacturing process of LCD or EL display, Product defects due to resist peeling can be suppressed and yield can be improved.

Claims (11)

  Contains 1.5-20% by weight of organic acid, 0.0007-0.73% by weight of chloride ion, 0.00003-3.7% by weight of ammonium ion and the balance water, and with respect to ammonium ion A resist adhesion improver in which the molar concentration ratio of chloride ions is in the range of 0.1 to 10.   The resist adhesion improver according to claim 1, wherein the molar concentration ratio of chloride ion to ammonium ion is in the range of 0.5-5.   The resist adhesion improver according to claim 1 or 2, wherein the content of the organic acid is 1.5 to 17% by weight.   The resist adhesion improver according to claim 3, wherein the content of the organic acid is 3 to 7% by weight.   The molar concentration ratio of chloride ion to ammonium ion is in the range of 0.6 to 4.9, and the total content of chloride ion and ammonium ion is 0.00076 to 1.07% by weight. Resist adhesion improver.   The resist adhesion improver according to claim 1, wherein the organic acid is a monovalent carboxylic acid or a polyvalent carboxylic acid.   The resist adhesion improvement according to claim 6, wherein the organic acid is at least one selected from the group consisting of acetic acid, formic acid, butyric acid, citric acid, succinic acid, malonic acid, succinic acid, acrylic acid, methacrylic acid and maleic acid. Agent.   The resist adhesion improver according to claim 1, wherein the chloride ion source is at least one selected from the group consisting of hydrochloric acid and ammonium chloride.   The resist adhesion improver according to claim 1, wherein the ammonium ion source is at least one selected from the group consisting of aqueous ammonia and ammonium chloride.   The resist adhesion improver according to claim 1, wherein ammonium chloride is used as a supply source of chloride ions and ammonium ions.   A step of forming a photosensitive resist film on the copper film formed on the substrate surface, and etching the copper film portion from which the resist film is removed by exposing and developing the photosensitive resist film through a pattern mask. In the copper wiring manufacturing method including the step of etching with a liquid, when the photosensitive resist film is formed on the copper film, the surface of the copper film is formed using the resist adhesion improver according to claim 1. A copper wiring manufacturing method comprising forming a photosensitive resist film on a copper film after the treatment.

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